Fuel for spark ignition engines



United States Patent 3,009,790 FUEL FOR SPARK IGNITION ENGINES John P.Pellegrini, Jr., and Helen I. Thayer, Pittsburgh,

Pa., assignors to Gulf Research & Development Company, Pittsburgh, Pa.,a corporation of Delaware No Drawing. Filed Apr. 5, 1957, Ser. No.650,838

11 Claims. (Cl. 44-58) This invention relates to fuels and moreparticularly to leaded gasolines for high-compression, spark ignitionengines.

It has long been recognized that for greater economy with respect tofuel requirement and greater efiiciency in the operation of agasoline-powered, spark ignition engine high-compression ratios aredesired. As a result, several automobile manufacturers have increasedthe compression ratios of their spark ignition engines to 8.5 :1 andeven as high as :1, the future trend of the automotive industryindicating that substantially all engines will beoperating at such highor higher compression ratios in the foreseeable future. In order toobtain smooth engine operation at these high compression ratios undervarious driving conditions itis necessary to employ a fuel having highoctane numbers as determined by both the motor method (ASTM: D357-53)and theresearch method (ASTM: D908-55).

Smooth operation at'high speeds under open-road conditions in modernhigh-compression engines usually requires a fuel having a motor octanenumber of at least about 85. Smooth operation in the same engines atlower speeds under city driving conditions where frequent accelerationsare encountered usually requires a fuel having a research octane numberof at least about 95. An opti- I mum fuel for present dayuse is thus onewhich has a re-.

search octane number of at least about 95"and a'sensitivity of about 8to 12. 'By sensitivity, we intend to indicate the spread or differentialbetween the octane numbers as determined by the motor method and theresearch method. Of course, if fuels are available whose motor andresearch octane numbers coincide at levels of 95 or more, thesensitivity ,of such fuels can bein the order of'l to 2 or less andstill result in desirable fuels for use in high-compression enginesunder both low:

speed and high-speed operation. a

In order to obtain fuels having both high motor and high research octanenumbersthe petroleum industry has developed numerous petroleumhydrocarbon conversion processes among which may be mentioned cracking,alkylation, ,aromatization, cyclization, isomerization, hydrogenatio'n,dehydrogenation, hydroisomerization, poly- 3,009,790 Patented Nov. 21,1961 ICC fuels or a blend of fuels obtained by one or more of theabove-mentioned hydrocarbon conversion processes. However, a smallamount of straight-run gasoline, in some instances, may be blended withthe fuels obtained by a conversion process.

To improve still further the octane ratings of the fuels obtained by thevarious conversion processes, the petroleum industry, in most instances,has resorted to the use of various anti-knock agents among which istetraethyl lead. While the addition of tetraethyl lead to gasolinesobtained by one or more conversion processes improves their motor andresearch octane numbers, the resulting fuels have certain disadvantagesarising from the presence of the lead. One of the chief objections tothe use of gasolines containing tetraethyl lead, i.e., leaded gasolines,arises from the tendency of such fuels upon being burned to formdecomposition products of tetraethyl lead, a portion of which productsaredeposited on the walls of the combustion chambers of the engine andon the electrodes and insulators of the spark plugs, thus reducing theefiiciency of the engine and offsetting to some extent the increasedefficiency obtained by using an engine having a high compression ratio.

In an attempt to overcome the detrimental effect of the deposits oftetraethyl lead decomposition-products in an engine, various scavengingagents have been added to the fuel to change the form of the tetraethyllead decomposition products to those which are more volatile and thusless likely to be deposited within the engine. For example, variousvolatile alkyl halides such as ethylene dibromide and/ or ethylenedichloride have been used with tetraethyl lead to produce thecorresponding halides of lead-which are more volatile than the oxides.The

volatile alkyl halides, however, have not completely overis frequentlyevidenced by engine knocking. The knocking thus encountered is thatassociated with preignition of the fuel in the combustion chamber of aspark ignition engine. This knocking associated With preignition shouldI not be confused with knocking due to explosive auto I ignition of theunburned portion of the fuel-air mixture merization,hydrodesulfurization,reforming, hydroforming, polyforming, Platformingand combinations of two or more of such processes. These processesproduce hydrocarbons boiling in the gasoline boiling point range whichhave engine performance characteristics markedly superior to the chargestock and to comparable boiling hydrocarbons found in straight-rungasolines. In general, straight-run gasolines are more paraffinic andless olefinic and aromatic than gasolinesobtained, for example, by acracking process. Straight-run gasolines, per'se,

even'when fortified with tetraethyl lead generally do not give the highmotor and research octane numbers re quired for smooth performance inpresent day engines. This ,invention is concernedprimarily, therefore,with to be traversed by the normal flame from the spark plug] We havefound that a motor fuel, and particularly a gasoline obtained by aconversion process and containing tetraethyl lead in an amountsuflicient to produce a gaso line fuel composition having amotor octanenumber of at least about and a research octane number of at least aboutis markedly improved'withrespect to its preignition characteristics byincorporating therein a small amount of a tri(alkoxyalkyl) followingstructural formula:

R1 R2 R- o-oHcn ',o

R R, -(O-(ilHCH):O-P=0 U R, R,

-(00HCH),0

phosphate having the 3 7 wherein R, R and R are alkyl groups containingabout 1 to about carbon atoms, R and R are selected from the groupconsisting of hydrogen and alkyl groups con taining about 1 to about 3carbon atoms and x is an integer from 1 to 2.

We prefer to employ the tri(alkoxyalkyl) phosphates which are soluble ingasoline and substantially insoluble in water, since gasolineoccasionally comes in contact with water thus giving rise to thepossible loss of watersoluble tri(alkoxyalkyl) phosphates.Water-solubility of the tri(alkoxyalkyl) phosphates is dependent to alarge extent upon the sum of the number of carbon atoms in the groupsdesignated as R, R and R in the structural formula shown above. Thus,while the sum of the carbon atoms in R, R and R" can be between 3 and30, the sum of the carbon atoms to insure substantial water-insolubilityis at least 8. The sum of the carbon atoms in the three groups is atleast 6 but can be 6 to 24. The higher mo phosphate, in preparinggasoline fuel compositions of the invention, these compounds are watersoluble and therefore are subject to loss from a fuel compositioncontaining them if the composition comes in contact with water. For thisreason, tri(methoxyethyl) phosphate and tri- (ethoxyethyl) phosphate areless desirable than a compound such as di(et'hoxyethyl) butoxyethylphosphate, tri(propoxyethyl) phosphate or tri(butoxyethyl) phos; phate.The latter compound, for example, is completely soluble in gasoline at25 C., and has a solubility in water at 25 C. of only about 0.11percent.

The groups designated as R, R and R" in the struc tural formula shownhereinabove can be either alike or different. Likewise, R and R can beeither alike or different groups. From the standpoint of preparation,however, compounds are preferred where R=R=R.

Specific examples of some of the tri(alkoxyalky1) phosphates which canbe used in accordance with our invention are I Tri(methoxyethyl)phosphate Tri(1-methoxy-2-propyl) phosphate Tri-(Lmethoxy-l-butyl)phosphate T ri(1-methoxy-2-butyl) phosphate Tri(2-metl1oxy-3-butyl)phosphate Tri(2-methoxy-'1-pentyl) phosphate Tri(3-methoxy-2-hexy-l)phosphate Tri(3-meth0xy-4-heptyl) phosphate Tri(4-methoxy-5-octyl)phosphate Di(rnethoxyethyl) propoxyethyl phosphate Di(methoxyethyl)butoxyethyl phosphate Di(propoxyethyl) methoxyethyl phosphateDi(propoxyethyl) butoxyethyl phosphate Tri(ethoxyethy-l) phosphateTri(2-ethoxy-l-propyl) phosphate Tri(1ethoxy-2-butyl) phosphateTri(3-ethoXy-2-hexyl) phosphate Tri(4-ethoxy-3-heptyl) phosphateTri(propoxyethyl) phosphate Tri(1-propoxy-2-propy1) phosphateTri(2-propoxy-3-butyl) phosphate 4 Tri(3-propoxy-4-heptyl) phosphate 'Iri(but0xyethyl) phosphate Tri(2-butoxy-1-propyl) phosphateTri(2-butoxy-3-butyl) phosphate Tri(4-butoxy-3-heptyl) phosphate ITri(4-butoxy-5-octyl) phosphate Tri-(pentoxyethyl) phosphateTri(hexoxyethyl) phosphate Tri(heptoxyethyl) phosphate Tri(octoxyethyl)phosphate Tri(nonoxyethyl) phosphate Tri(decoxyethyl) phosphateTri(ethoxyethoxyethyl) phosphate Tri[2-(2-ethoxy-l-propoxy)-l-pr0pyl]phosphate Tri{2-(2-ethoxy-3-butoxy)-3-butyl] phosphateTri[3(3-ethoxy-2-hexoxy) -2-hexyl] phosphateTri[3-(3-propoxy-2-butoxy)-2-butyl] phosphate Tri[4-(4-propoxy-3-hexoxy)-3-hexyl] phosphate Tri[2-(2-butoxy-1-propoxy)-1-propyl] phosphateTri[3-(3-butoxy-2-butoxy)-2-butyl] phosphateTri[4-(4-butoxy-3-hexoxy)-3-hexyl] phosphate The tri(alkoxyalkyl)phosphates can readily be prepared by conventional means includingreacting phosphorus oxychloride with the desired alkoxyalkyl alcohol.The following procedures are typical for preparing the tri-(allsoxyalkyl) phosphates which can 'be used in the fuel compositions ofthe invention.

TRI METHO-XYETHYL) PHOSPHATE 20.2 parts by weight of phosphorusoxychloride are gradually added to parts by weight of methoxyethanolwhile the mixture is stirred and the temperature held at about 5 to 10C. Nitrogen gas then is passed through the mixture for eight hours atroom temperature to remove hydrogen chloride. Upon completion of thereaction anhydrous sodium carbonate is added until the reaction mixtureis neutral.- The tri(rnethoxyethyl). phosphate then is isolated byfiltering the mixture, and distilling the filtrate in vacuo, first at100 mm. Hg to remove the excess alcohol and other low boilingby-prodnets, and then at 1 mm. Hg. The boiling point of the product thusobtained is to 13-6. C. at 1 mm. Hg.

The product is a colorless liquid and has an index of refraction of1.4352 at 20 C. The phosphorus content of the product so obtained is11.11 percent as compared with the theoretical amount of 11.37,. Theyield is about.

sixty-five percent of theory.

TRI(BUTOXYETHYL) PHOSPHATE To 100 pants by weight of butoxyethanol 21.7parts by weight of phosphorus oxychloride are added dropwise whilemaintaining the temperature of the mixture at 10 C. or lower. Thereaction mixture is then heated to 60.? C. and held at this point forthree hours. The hydrogen chloride evolved is conveniently removed by agas absorption trap. The mixture is then cooled'to room tcm-,

perature andan aqueous solution of sodium bicarbonate 1s added until thereaction mixture is neutral. The organic layer is' separated, waterwashed and distilled in vacuo. After the excess alcohol has beenremoved, the

erties of the tr i(butoxyethyl) phosphate so obtained are as follows:

Freezing point, C --70 Pour point, C 65 Flash point, F

l 340 Fire point, F 470 Viscosity at 20 C., centipoises 1 1.7 Surfacetension at. 20 C., dynes/cm 28.8

TRI ETHOXYETHOXYETHYL) PHOSPHATE Into 100 parts by weight ofethoxyethoxyethanol 1 1,4 i

parts by weight of phosphorus oxychloride are added dropwise while themixture is stirred and the temperature kept at 20 to 30 C. The mixtureis then blown with nitrogen for three to four hours tov remove hydrogenchloride and the temperature raised to 50 to 60 C. The reaction mixtureis cooled to room temperature and anhydrous sodium bicarbonate is addeduntil the reaction mixture is neutral. After separating the solids byfiltration, the filtrate is distilled at 60 to 70 mm. pressure to removethe excess alcohol until the pot temperature reaches about 140 C. Thetri(ethoxyethoxyethyl) phosphate which remains in the pot is notdistilled, but is sufliciently pure for use in the compositions of theinvention as obtained. The product is a light yellow oil having aphosphorus content of 7.50. The theoretical phosphorus content is 6.93.The yield is about ninety to ninety-five percent of theory.

The amount of tri(alkoxyalkyl) phosphate required to impart improvedpreignition characteristics to the gasoline fuels, i.e., hydrocarbonmixtures boiling in the gasoline boiling range, depends upon thetetraethyl lead content of the particular fuel encountered, and upon theparticular tri(alkoxyalkyl) phosphate which is selected. For thisreason, the amount is more significant and can be more accuratelyexpressed in terms of that which is theoretically required to convertthe lead introduced into the fuel in the form of tetraethyl lead to leadorthophosphate. While improved results can be obtained with very smallamounts, amounts corresponding to at least about 0.1 times thattheoretically required to convert the lead to lead phosphate arepreferred. Especially good results are obtained by using about 0.2 toabout 0.5 times the theoretical amount required. In general, we pre ferto use an amount not more than the amount theoretically required toconvert all of the lead to lead orthophosphate. Amounts greater than thetheoretical amount can be employed, but for economic reasons, we preferto use only the amount required to give the desired improvement.Therefore, we prefer to employ an amount equal to about 0.2 to about 0.5times that theoretically required to convert the lead to leadorthophosphate. In view of the fact that the amount of tetraethyl leadin the gasoline varies from one fuel to another, it is difiicultto'state on a weight basis the amount of a particular compound basedupon the weight of the gasoline. However, once knowing the amount oftetraethyl lead present in the gasoline, it is an easy matter tocalculate the amount of the particular compound required on a weightbasis. Mos-t gasolines on the market today contain between about one andabout three cubic centimeters of tetraethyl. lead per gallon ofgasoline. Based upon a gasoline having a gravity of about 54 API andcontaining about one cubic centimeter of tetraethyl lead, we havedetermined that the amount of the tri- (butoxyethyl) phosphatecorresponding to 0.1 to 1.0 theories is about 0.0047 to about 0.047percent by weight based on the gasoline. It the same gasoline contains 3cubic centimeters of tetraethyl lead, then the tri(butoxyethyl)phosphate for 0.1 to 1.0 theories is about 0.014 to about 0.14 percentby weight. Thus, the normally useful concentration range for a 54 APIgasoline containing about 1 to about 3 cubic centimeters of tetraethyllead is about 0.0047 to about 0.14 percent. Although greaterconcentrations can be employed to advantage in some instances, noadditional benefits with respect to preignition are achieved by the useof greater concentrations. For most currently marketed commercialgasolines, about-0.003 to about 0.45 weight percent of thetri(-alkoxyalkyl) phosphate is usually suflicient to achieve asatisfactory reduction in the engine preignition tendencies of the fuel.The amount within this range should, of course, be suflicienttoincorporate between about 0.1 and about 1.0 times that theoreticallyrequired to convert the lead to lead phosphate.

a It will be understood, amount on a weight basis for one particularcompound may not be the optimum amount for another compound.

One reason for this is that the efiectiveness of the COD):

pounds may vary from one compound to another. Another reason is that themolecular Weight of one com-' pound may be twice the molecular weight ofanother compound,-so that to obtain an equivalent amount 04? phosphoruswhen using the compound having the greater molecular weight, one isrequired to use twice the amount In any event, the amountof thetri(a1koxyaikyl) phosphate used is suflicient of compound on a weightbasis.

to give marked preignition improvement.

The tri(alkoxyalky1) phosphate can be either chemically pure or it cancomprise a commercial product which may contain a small amount of thealkoxyalkanol from which the corresponding tri(alkoxy alkyl) phosphatewas prepared or other neutral impurities. For example, when usingtri(butoxyethy1) phosphate, a small amount of butoxyethanol can bepresent without deleteriously affecting the improved preigniu'oncharacteristicsof the fuel.

The gasoline fuel composition to which the tri(alkoxyalkyl) phosphate isadded comprises a mixture of hydrocarbons boiling in the gasolineboiling range having a motor octane number (leaded) i of at least about85 and a research octane number (leaded) of at least about 95. Themixture of hydrocarbons can be obtained by at least one of the petroleumconversion processes including cracking, alkylation, aromatization,cyclization, isomerizatiorn, hydrogenation, dehydrogenation,hydroisomerization, polymerization, hydrodesulfurization, reforming, hy-

drofotrming, polyforming, Platforming, and combinations of two or moresuch processes, as well as by the Fischer-Tropsch and related processes.While current straight-run gasoline has octanenumbers too low to qualifyas the sole'hydrooarbon component of gasoline fuel compositions withinthe scope of this invention, a-

small amount of straight-run gasoline can be blended with thehydrocarbon mixture obtained by one or more of the designated conversionprocesses provided the resulting mixture has a motor octane number(leaded) of at least about and a research octane number (leaded) of atleast about 95. A preferred gasoline fuel composition comprises a blendof hydrocarbons obtained by catalytic cracking, Platfocrming andalkylation processes.

In addition to the tri(a1koxyalkyl) compound and tetraethyl lead, thegasoline fuel composition of our invention can contain other gasolineimprovement agents including upper cylinder lubricants, corrosion andoxidation inhibitors, conventional alkyl halide lead scavenging agents,alcoholic anti-stalling agents,,metal deactivators, dehazing .agents,anti-rust additives, other ignition control agents,

dyes and the like.

When an upper cylinder lubricant is employed it is genorally used in anamount of from about 0.25 to about 0.75

percent by volume of the composition, e.g., 0.5 volume percent. This oilshould bea light lubricating oil distillate, e.g., one having aviscosity at F. of from about 50 to about 500 Saybolt Universal'seconds,e.g., about 100 SUS. Although highly paraflinic lubricating distillatescan be used, lubricating distillates obtained from Coastal or naphthenictype crudeoils are preferred because of their superior solventproperties. The lubricating oil can be solvent-treated, acid-treated,or'otherwise refined.

When an oxidation inhibitor is desired, any of the conventionalinhibitors can be utilized. The alkylated phenols, e.g.,2,4,o-tni-tertiary-butylphenol, 2,6-di-tertiarybutyl-4-methylphenol,2,2-bis(2-hydroxy-3-tertiary-butyl- 5-methylphenyl) propane andbis(2-hydroxy-3-tertiarybutyd-S-methylphenyl) methane, because of theirhydrocarbon-solubility and water-insolubili-ty characteristics arepreferred oxidation inhibitors. Such inhibitors when used areincorporated in the gasoline fuel composition in of course,- that theoptimum amounts. of from about 0.001 to about 0.02 percent by weight ofthe composition, e.g., 0.007 weight percent.

Exemplary of other specific improvement agentswhich we can use areN,N-disalicylidene-1:Z-diaminopropane as a metal deactivator and thecocoamine salt of isoamyl octyl acid orthophosphate as a rust inhibitoragent. The

metal ,deactivator. is generally used in small amounts of the, order ofabout 0.0003 to about 0.001 percent by weight based on the fuelcomposition. The rust" inhibitor is generally'used in small amountsofthe order of about 0.002'to about 0.008 percent by weight based on thefuel composition.

The cocoamine salt of isoamyl octyl. acid orthophosphate and itspreparation are fully described in U.S.

Patent .No. 2,371,851 which issued. on March 20, 1945, to Herschel G.Smith and Troy L. Cantrell. As disclosed in said patent, the cocoaminesalt of isoamyl octylacid phosphate can be'readily prepared by reactingcocoamine with isoamyl octyl acid orthophosphate in approximatelyequimolecular ratios, the reaction being so controlled as to producesubstantially neutral reaction mixtures having a pH value within therange of 5.5 to 7.5, as illustrated in Examples. 1 and 2 of that patent.ture of amines prepared from coconut oil fatty acids, and contains. apredominant amount of n-dodecyl amine (l auryl amine), together withminor amounts of n-octyl, n-decyl, n-tetradecyh. n-hexadecyl,n-octadecyl, and noctadecenylamines. The isoamyl octyl acid phosphateemployed in a di-ester of onthophosphoric acid having the followingstructural formula:

I n n n o H H HaC-( 3( J( l-Oi O-(il( J-CiHo omen (in it can hol,isopropyl alcohol, isooctyl alcohol, decyl alcohol,-

methylal, acetal, propylal and isopropylal, tetraethoxy propane,dimethyl metal of isooctyl aldehyde, ethyl ether, cyclohexano-l,acetone, an alkoxyalkanol, or the like. The concentrate, of course, cancontain other conventional gasoline. -improvement agents, such asanti-oxidants, typical anti-stalling agents, anti-knock agents, ametaldeactivator, an: upper cylinder lubricant, an alkylhalide leadscavenging agent, a dehazing agent, anti-rust additives, other ignitioncontrol agents, dyes and the like. Since the amount of tri(alkoxyalkyl)phosphate depends to some extent upon the amount of the tetraethyl leadpresent, this method of adding the compound to the gasoline serves as aconvenient way of adding the;.correct amount of tri(alkoxyalkyl)phosphate and tetraethyl leadsimultaneously. Thus, a gasoline-benefitingconcentrate can be.

made by admixing tetraethyl lead or commercially available mixtures oftetraethyl lead and a halide of ethylene with the tri(alkoxyalkyl)phosphate wherein the tri(alk- Cocoamine is a mixoxyalkyl) phosphate ispresent in an amount bet-ween about 0.1 and about 1.0 times thetheoretical amount required to convert the lead of the tetraethyl leadto lead orthophosphate.

The proportions of the constituents in such a gasolinebenefitingconcentrate may vary depending upon the characteristics of the basegasoline to which the concentrate is to be added as well as thecompression ratio of the engine in which the gasoline is to be used.Good results can be obtained, however, with a composition consistingofabout 23 to about 60 percent by weight of tetraethyl lead, about 13 toabout 36 percent by weight of a mixture of ethylene halides and about 3to about 63 percent by weight of a -tn'(alkoxyalkyl) phosphate, the

tri(alkoxyalkyl) phosphate being present in at least 10.1

times the theoretical amount required to convert the lead in thetetraethyl lead to lead phosphate.

One convenient method of preparing a gasoline-benefiting concentrate isto start with a commercially available product comprising tetraethyllead and the halides of ethylene. One such commercially availableproduct consists of about 61.5 percent by'weight of tetraethyl lead,about 17.9 percent by Weight of ethylene dibromid'e and about 18.8percent by weight of ethylene dichloride.

This commercially available product has a specific gravity Grams Percentby Weight Tetraethyl lead 4. 94 53. 2 Ethylene dibromide 1. 43 15.4Ethylene dichloride l. 51 16. 3 Tri(butoxyethyl) phosphate 1. 23 13. 3

Toincorporate three cubic centimeters of tretaethyl lead in a gallon ofgasoline, the above concentrate is added to the base gasoline in amountsof about 9.26 grams per gallon. The gasoline-benefiting concentrate thusprepared exhibited no deterioration upon prolonged storage in the darkat room temperature.

The amount of the gasoline-benefiting concentrate added to gasoline willvary depending upon the octane improvement desired; Ordinarily, however,the concentrate is added in an amount sufficient to incorporate betweenabout one and about three cubic centimeters of tetraethyl lead in agallon of gasoline.

Although the tn'(alkoxyalkyl) phosphates of this invention are utilizedprimarily as preignition agents, they are additionally useful in thatthey give increased valve life and spark plug life andthey impartvaluable anti-rust, oxidation stability and anti-stalling properties togasoline compositions when used in preignition-inhibiting amounts.

The gasoline compositions of this invention and their preparation areillustrated in detail by the following specific examples.

Example I A gasoline composition having excellent preignitioncharacteristics was prepared by incorporating 0.825 gram oftri(butoxyethyl) phosphate in a gallonof the base gasoline(approximately 0.029 weight percent). The base gasoline was a blendedgasoline made up of catalyti cally cracked gasoline, alkylate andPlatformate. The base gasoline contained about 3 cubic centimeters (4.94grams) of tetraethyl lead per gallon of gasoline. addition, the basegasoline contained as a oxidation inhibitor2,6-di-tertiary-butyl-4-methylphenol (30 lbs/1000 bbls.) and as ametaldeactivator N,N'-disalicylidene 1:2-diaminopropane (l lb./1000 bbls.).The tri(-butoxyethyl) phosphate thus comprised about 0.2 times thetheoretical amount required to convert the lead of the tetraethyl leadto lead orthophosphate. Typical samples of the base gasoline and thebase gasoline containing 0.029 percent of the tri(butoxyethyl) phosphatehad the following inspections:

With no With tri (bu- 0.029% trl toxyethyl) (butoxyphosphate ethyl)phosphate Gravity, API 53. 7 54. Sp. gr., 60/60 F 0. 7640 O. 7628Sulfur, L, percent 0. 04 0. 04 Copper strip test, 122 F., 3 hrs 1A 1ACopper dish gum: mg./100 m1. ASTM: D910- 53T g 1 4g Existent gum,mg./l00 ml Oxidation stability, min.. 733 861 Bromine number 32 34 Knockrating:

Motor method 89.3 89. 0 Research method 99. 7 99. 4 TEL, mL/gal 3. 04 3.04 Vapor pressure, Reid, lb 5. 5. 3 Distillation, gasoline:

Over point, F 104 112 End point, F 374 377 evap. at F 161 162 50 245 24490" 309 818 Recovery- 99. 2 98. 2 Residue 0. 5 1. 2

1 This increase over the base gasoline is not indicative of an increasein gum formation. Reason for increase is that tr1(butoxyethyl) phosphateis not volatile under the conditions of the gum test.

Example II Another suitable composition was prepared in the manner ofthe foregoing Example I by incorporating 1.24 grams of tri(butoxyethyl)phosphate in a gallon of the base gasoline (approximately 0.043 weightpercent). The tri(butoxyethyl) phosphate thus comprised about 0.3 timesthe theoretical amount required to convert the lead to leadorthophosphate. 3

Example III Another composition was prepared in the manner of theforegoing Example I by incorporating 1.65 grams of tri(butoxyethyl)phosphate in a gallon of base gasoline (approximately 0.057 weightpercent). The tri(butoxyethyl) phosphate thus comprised about 0.4 timesthe theoretical amount required to convert the lead to leadorthophosphate.

Example IV An additional composition was prepared in the manner of theforegoing Example I by incorporating 4.14 grams of tri(butoxyethyl)phosphate in a gallon of gasoline. The tri(butoxyethyl) phosphate thuscomprised about 1.0 times the theoretical amount required to convert thelead to lead orthophosphate.

Example V An additional gasoline composition having excellentpreignition characteristics combined with good uppercylinder lubricationwas prepared by adding a lubricating oil distillate to the base gasolineand then incorporating in the oil-containing gasoline fuel composition1.24 grams of tri(butoxyethyl) phosphate per gallon of gasoline fuelcomposition (approximately 0.043 weight percent). The

Gravity, API L-bs./gal., 60 F Example VI Other suitable compositionswere prepared by admixture of the cocoamine salt of 3-methylbutylZ-ethylhexyl or-thophosphoric acid to the oil-containing gasoline fuelcomposition of Example V. The cocoamine dialkyl o-phosphate (84 weightpercent oil concentrate) in these compositions was added to the gasolinein the ratios of about 5 pounds and about 16 pounds per 1000 barrels(approximately 0.0019 and 0.0060 percent by weight active component).

Example VII Another satisfactory composition in accordance with thisinvention was prepared in the manner set forth in the foregoing examplesby incorporating in the base gasoline 0.564 gram (approximately 0.020weight percent) of tri- (methoxyethyl) phosphate. The tri(methoxyethy1)phosphate thus comprised about 0.2 times the theoretical amount requiredto convert the lead to lead orthophosphate.

Example VIII Another satisfactory composition was prepared as indicatedin Example VII, except that tri(octoxyethyl) phosphate was used as thepreignition inhibitor.

Example IX Another satisfactory composition was prepared as indicated inExample VII, except that tri(ethoxyethoxyethyl) phosphate was used asthe preignition inhibitor.

' Example X Another satisfactory composition is prepared as indiciate'din ExampleVII, except that tri(3-methoxy-'4- heptyl) phosphate is usedas the preignition inhibitor.

Example XI Example XIV Another satisfactory gasolinecomposition isprepared by admixture of approximately 0.038 percent by weight of thecomposition of tri(propoxyethyl) phosphate with a base gasoline fuelcomposition having a lead content of about 3 cubic centimeters oftetraethyllead per gallon and containing 0.5 volume percent of a SUS at100 F. (approximate) lubricating distillate oil obtained from I.

a Coastal type crude.

Example XV Another-satisfactory gasoline composition is preparedsubstantially identically as indicated in Example XIV except thattri(octoxyethyl) phosphate is used as the preignition inhibitor.

The compositions described in the foregoing examples are illustrativeonly, and other tri(all oxyalkyl) phosphates disclosed herein can besubstituted in the foregoing specific compositions in the same orequivalent concentrations with goodresults.

An appreciable reduction-in preignition due to tetraethyl leaddecomposition product deposits is achieved by the use of the foregoinggasoline fuel compositions in internal combustion engines of thegasoline-powered, spark ignition type. For example, when thecompositions described in the examples are burned in an internalcombustion engine operated under conditions wherein noise,includingpreignition, knock or rumble would normally be encountered suchengine noise is markedly less than the noise encountered when the basegasoline is used alone.

In order to illustrate the improved preignition characteristicscbtainedwith a fuel of the invention, a test was employed in which the fuel wasburned in four commercially available spark-ignition engines. Theseengines, with the exception of Engine C which had a compression ratio of8.5 to 1, each had a compression ratio of 10 to 1. In this test, theengines were operated on a cycling schedule consisting of three minutesat 1500 r.p.m. at a 15 brake horsepower load, followed by a one-minuteidle at 450 rpm. The spark advance i-n-each instance was themanufacturers setting. The coolant temperatures in and out were 150 and160 F. (:5), respectively. The oil temperature in all instances was 180F. (:5 At the end of each twenty-four hours under the abovedescribedcycling schedule, noise requirement determinations were made. After thenoise requirement determinations were made, the engines were then putback on the cycling schedule for another twenty-four hours. The cyclingand noise requirement tests were continued for nine 24-hour periods.

The noise requirement deter'minations were made according 'to threesuccessive steps. If noise was encountered in step one, then steps twoand threewere omitted. If noise was: encountered instep two, then onlystep three was omitted. Noise in this-test is intended to includepreignition, normal knocking or rumble. The three successive stepsof thetest'are as follows:

(1) At a. speed of 1100 rpm. the throttle is opened to detent (that is,the rear barrels of the carburetor are just open) at l-inch Hg intakemanifold vacuum.

(2) The engine speed is increased to 1300 rpm. at 3- inch vacuum.

(3) The engine is acceleratedat IO-inch vacuum from. 1300 to 2000r.p.m., standard spark, and held at this setting for 3 seconds (throttleWide-open at end of 3-second period).

Aural observations are made at steps (1),. (2) and 3) and preignition,rumble and knock are recorded- Ratings are made on the tank fuel. (99research octane number) and the actual noise requirement determined bythe use of a set of commercial" reference fueis up to an octane numberof 113.5. For noise requirements in the range 113.5 to 120, leadedisoootane was used. Octane numbers above 100 are expressed in theapproved extension scale, \Mese octane numbers, which are:

Performance No.- 100 3 12 vert the lead to lead orthophosph'ate. Theresults of an additional (test are shown where 0.2 theories oftriifmethoxyethyl) phosphate was used. The results of still furthertests on fuel compositions containing an upper cylinder lubricant and acorrosion inhibitor are also shown.

Engine Fuel composition Base gasoline 111. 2 Base gasoline plus 0.2theories of tri(butoxyethyl) phosphate (Example I composition) Basegasoline plus 0.3 theories of tri(butoxyethyl) phosphate (Example IIcomposition) Base gasoline plus 0.4 theories of tri(butoxyethyl)phosphate (Example III composition) Base gasoline plus 0.3 theories oftriOautoxyethyl) phosphate and 0.5 vol. erccnt Coastal Lubricating OilExample V composition)" Base gasoline lus 0.2 theories of tri(methoxyet.yl) phosphate (Example VII composition)- Base gasoline plus 0.5 vol.percent Coastal Lubricating Oil and 5 pounds per 1,000 barrels ofgasoline of the cocoamine salt of 3-methylbuiziyl 2-ethylhoxylorthophosphorlc aci Base gasoline plus 0.3 theories of tri(butoxyethyl)phosphate, 0.5 vol. percent Coastal Lubricating Oil and 5 pounds per1,000 barrels of gasolineof the cocoamine salt of 3-methylbutylZ-ethylhexyl orthophosphoric acid (Example VI composition) The data inthe foregoing Table I clearly indicate the improvement obtained when asmall amount of rtri (butoxyethyl) phosphate is added to the basegasoline. It will be noted, for example, that the octane numberrequirement of the 10 to 1' compression ratio engines in which the basegasoline had been used was 120+. The octane number requirement of the8.5 to 1 compression ratio'engine (Engine C) in which the base gasolinehad been used was; 111.2. The octane number requirement when 'using fuelcompositions of the invention was markedly reduced in every instance.

TABLE II.2=1-HOUR PERIODSCFO SUSTAINED VIOLENT C PREIGNITION Engine Fuelcomposition It will be noted from the data in Table II that test EnginesA, B and D ran for five, three and two 24-hour periods, 'respectively,onthe basegasoline before sustained violent preignitionwas'encountered.When the engines were operated with fuel compositions of the invention,sustained violent pre'ignition' was not encountered, with one exception,evenat the end of nine 24-hour periods.

The fuel compositions of the invention show not only marked improvementwith respect to their preignition characteristics but also thereare'less deposits formed in the combustion chambers of the enginesoperated with the improved fuels. At the termination of the prior tests,

TABLE TIL-DEPOSIT WEIGHTS (GRAMS) Engine Fuel composition Base gasolineBase gasoline plus 0.2 theories of tri(butoxyethyl) phosphate (Example Icomposition). Base gasoline plus 0.3 theories of tri(butoxyethyl)phosphate (Example II composition Base gasoline plus 0.4 theories oftri(butoxyethy)l) phosphate (Example III composition Base gasoline plus0.3 theories of tri(butoxyethyl) phosphate and 0.5 vol. percent CoastalLubricating Oil (Example V composition) Base gasoline plus 0.2 theoriesof tri(methoxyethsgl) phosphate (Example VII composition Base gasolineplus 0.5 vol. percent Coastal Lubricating Oil and pounds per 1.000barrels of gasoline of the cocoamine salt of 3-methylbutyl 2-ethylhexylorthophosphoric acid Base gasoline plus 0.3 theories of tri(butoxyethyl)phosphate, 0.5 vol. percent Coastal Lubricating Oil and 5 pounds per1,000 barrels of gasoline of the cocoamine salt of 3- methylbutyl2-ethylhexyl orthophosphoric acid (Example VI composition) The data inTable III clearly indicate that the deposits formed in the combustionchambers of each of the test engines was less when using a gasolinecontaining a tri- (alkoxyalkyl) phosphate than when using the basegasoline alone. While the addition of an upper cylinder lubricant gavean increase in deposits in some tests the deposits were still less thanthose obtained with the base gasoline alone.

In order to illustrate further the improved results obtained with fuelcompositions of the invention, noise determinations were made inover-the-road fleet tests using four 1955 Cadillacs having a 10:1compression ratio. Two of the cars were run for 6500 miles using as afuel a base gasoline containing 0.2 theories of tri(butoxyethyl)phosphate (Example I composition). The other two cars were run for10,000 miles using as a fuel a base gasoline containing 0.3 theories oftri(butoxyethyl) phosphate (Example II composition). Comparative testswere made on the same cars using the base gasoline alone. During thefleet tests, the cars operating on the fuel containing 0.2 theories oftri(butoxyethyl) phosphate were driven on a level driving course at amaximum speed of 35 mph for'the entire 6500 miles. The cars operating onthe fuel containing 0.3 theories of tri(butoxyethyl) phosphate weredriven on a level driving course at a maximum speed of 35 mph. for 6,000miles, then over a hilly route at a maximum speed of 45 mph. for 2,000miles and finally over the level course at a maximum speed of 35 mph for2,000 miles. All of the cars were driven five days. a week, 7.5 hoursper day. At the end of every third day of operation, noise requirementdeterminations were made on a dynamometer. As in the case of themulticylinder stationary engines the fleet cars were rated first on tankfuel and then the ,noise requirement determined by using commercialreference fuels. In the case of the fleet cars, requirements weredetermined first at 2500 r.p.m. and then at 2000 r.p.m. The noiserequirements are expressed as octane numbers for either knock or rumbleat 2500 r.p.m. When the cars were operated with the base gasoline,the/test at 35 mph. was discontinued after 3800 miles inasmuch as theoctane requirement at the end of this period had become in excess of120. The test was continued at 45 mph. for an additional 2000 miles atthe end of which period the octane requirement leveled off at about 114.The cars operating on the fuel containing 0.2 theories. oftri(butoxyethyl) phosphate had average octane requirements of about99-100 during the entire 6,500 miles. The cars operating on the fuelcontaining 0.3 theories of tri(butoxyethyl) phosphate vhad averageoctane requirements of about 97 to 98 over the entire test. The resultsobtained with the fuel of the invention are thus in marked contrast withthe results obtained when using the base gasoline.

and of the cocoamine salt of isoamyl -octyl acid phosphate in additionto exhibiting improved noise .characteristics, i.e., less preignition,knock and rumble, also show improved anti-stalling characteristics. Forexample, when the composition of Example VI containing approximatelyatmospheric conditions, the number of engine stalls due to carburetoricing was markedly less for this composition than for an otherwiseidentical composition but containing no tri(butoxyethyl) phosphate.

The improved anti-stalling characteristics were determined in a 1954Plymouth operating with an intake air temperature of 35 to 40 F., and arelative humidity of percent. In making the determinations, the enginewas cold when started. The engine then was accelerated and maintained at1500 r.p.m. for 1 minute after which the engine was decelerated to idlefor /2 minute. At this time the stalling characteristics were observedand recorded. Ifthe engine stalled, the above cycle was repeated. -Whenthe composition of Example VI was used as a fuel, there were 2 stalls in11 cycles. When the comparative composition containing notri(butoxyethyl) phosphate was used, there were 5 stalls in 13 cycles.Tn'(butoxyethyl) phosphate thus effected about a 50 percent reduction inthe number of stalls.

The increased valve life imparted to engines operating with a fuel ofthe invention has been determined with a Chevrolet-6 engine. Inmakingthis determination, the engine is operated on a cycling scheduleconsisting of 45 minutes at 3150 r.p.m. at a 30 horsepower load, 10min-. utes at 3150 r.p.m. at a 60 horsepower load and then 5 valvesfail. The results of the valve life tests are sum-.- marized in TableIV.

TABLE IV.VALVE LIFE TESTS Valve life in hours as measured by- Fuelcomposition r 1st 2nd, 3rd

failure failure failure Base gasoline plus 0.5 vol. percent CoastalLubricating Oil and 5pounds per 1,000 barrels of gasoline of thecocoamine salt of 3-methylbutyl 2-ethylhexyl orthophosphoric acid 66 9999 Base gasoline plus 0.3 theories of tri(butoxyethyl) phosphate,0.5,,vol. percent Coastal. Lubricating'Oil and.5 pounds per 1,000barrels of gasoline of the-cocoamine salt of 3- -methylbutyl2-ethylhexyl orthophosphoric acid (Example VI composition) 253 -310 374Thedata in Table. IV clearly indicate, the increased valve life obtainedwhen operating an engine with a composition of the invention as comparedwith the base gaso- The fuel compositions of the present invention when1 containing a small amount of upper cylinder lubricant line.. It willbe noted, for example, that when the engine was operated with a fuel ofthe invention (Example VI composition) under the severe test conditions,the third valve failure did not occur until 374 hours. When thecomparative composition. containing no tri(butoxyethy1) phosphate wasused, the third valve failed within 99 hours. The tri(butoxyethyl)phosphate thus eifected about a 275 percent increase in valve life.

While our invention is described above with reference to variousspecific examples and embodiments, it will be understood that theinvention is not limited to such examples and embodiments and may bevariously practiced within the scope of the claims hereinafter made.

We claim:

1. A gasoline motor fuel comprising a major amount of gasolinecontaining tetraethyl lead in an amount sufficient to produce a gasolinefuel composition having a motor octane number of at least about 85 and aresearch octane number of at least about 95 and between about 0.1 andabout 1.0 times the theoretical amount of a tri (alkoxyalkyl) phosphaterequired to convert the lead to lead phosphate, said tri(alkoxyalkyl)phosphate having the structural formula:

wherein R, R and R" are alkyl groups containing about 1 to about carbonatoms, R and R are selected from the group consisting of hydrogen andalkyl groups containing about 1 to about 3 carbon atoms and x is aninteger from 1 to 2.

2. Agasoline motor fuel comprising a major amount of gasoline containingtetraethyl lead in an amount sutficient to produce a gasoline fuelcomposition having a motor octane number of at least'about 85 and aresearch octane number of at leastabout 95 and between about 0.003 andabout 0.45 percent by weight, based on the gasoline, of atri(alkoxyalkyl) phosphate having the structural formula:

R-(O-CHCHhO wherein R, R and R" are alkyl groups c'ontainingabout 1 toabout 10 carbon atoms, R and R 'are selected from the group consistingof hydrogen and alkyl groups containing about 1 to about 3 carbon atomsand x is an integer from 1 to 2, the amount of the tri(alkoxyalkyl)phosphate present corresponding to at least 0.1 times the theoreticalamount required to con'vert the lead to lead phosphate.

3. The motor fuel. composition of claim 2, wherein the sum of the carbonatoms in R, R and R" is at least 8 and R and R are hydrogen.

4. A gasoline motor fuel comprising a major amount of gasolinecontaining tetraethyl leadin an amount sulfieient to produce a gasolinefuel composition having a motor octane number of at least about 85 and aresearch octane number of at least about 95 and between about 0.0047 andabout 0.14 percent by weight, based on the gasoline, of tri(butoxyethyl)phosphate, the amount of the tri(butoxyethyl) phosphate corresponding toat least about 0.1 times the theoretical amount required to convert thelead'to lead phosphate.

5. A gasoline motor fuel comprising a major amount of gasolinecontaining about 1 to about 3 cubic centimeters of tetraethyl lead pergallon of gasoline to produce a gasoline fuel composition having a motoroctane number of at least about and research octane number of at leastabout and between about 0.1 and about 1.0 times the theoretical amountof tri (butoxyethyl) phosphate required to convert the lead to leadphosphate.

6. A gasoline motor fuel comprising a major amount of gasolinecontaining about 1 to about 3 cubic centimeters of tetraethyl lead pergallon of gasoline to produce a gasoline fuel composition having a motoroctane number of at least about 85 and a research octane number of atleast about 95, between about 00047 and about 0.14 percent by weight oftri(butoxyethyl) phosphate, the tri(butoxyethyl) phosphate comprising atleast about 0.1 times the theoretical amount required to convert thelead in said tetraethyl lead to lead phosphate and about 0.25 to about0.75 percent by volume of a light lubricating distillate oil having aviscosity at F. of from about 50 to about 500 Saybolt Universal seconds.

7. A gasoline motor fuel comprising a major amount of gasolinecontaining about 1 to about 3 cubic centimeters of tetraethyl lead pergallon of gasoline to produce a gasoline fuel composition having a motoroctane number of at least about 85 and a research octane number of atleast about 95, between about 0.0047 and about 0.14 percent by weight oftri(butoxyethyl) phosphate, the tri(buto)ryethyl) phosphate comprisingat least about 0.1 times the theoretical amount required to convert thelead in said tetraethyl lead to lead phosphate, about 0.25 to about 0.75percent by volume of a light lubricating distillate oil having aviscosity at 100 F. of from about 50 to about 500 Saybolt Universalseconds I and about 0.002 to about 0.008 .percent by weight of the 0.1times the theoretical amount required to convert the lead in saidtetraethyl lead to lead phosphate, about 0.25 to about 0.75 percent byvolume of a light lubricating distillate oil having a viscosity at 100F. of from about 50 to about 500 Saybolt Universal seconds, about 0.002to about 0.008 percent by weight of the cocoamine salt of isoamyl octylacid phosphate, about 0.001 to about 0.02 percent by weight of2,6-di-tertiary-butyl-4- methylphenol and about 0.0003 to about 0.001percent by weight of N,N-disalicylidene-l:Z-diaminopropane.

9. A gasoline motor fuel comprising a major amount of gasolinecontaining about 3 cubic centimeters of tetraethyl lead per gallon ofgasoline to produce a gasoline fuel composition having a motor octanenumber of about 89 and a research octane number of about 99, about 0.043percent by weight of tri(butoxyethyl) phosphate, the tri(bu toxyethyl)phosphate comprising abfout 0.3 times the theoretical amount required toconvert the lead in said tetraethyl lead to lead phosphate, about 0.5percent by volume of a light lubricating distillate oil having aviscosity at 100 F. of about 100 Saybolt Universal seconds, about 0.002to about 0.006 percent by weight of the cocoamine salt of isoamyl octylacid phosphate, about 0.007 percent by weightof.2,6-di-tertiary-butyl-4-methylphenol and about 0.004 percent byweight of N,N'-disalicylidene-l Z-diaminoprop ane.

10. A gasoline benefiting concentrate comprising a major amount oftetraethyl lead and about 0.1 to about 1.0 times the theoretical amountof a tri(alkoxyalkyl) phosphate required to convert the lead to leadphosphate,

wherein R, R and R" are alkyl groups containing about 1 to about 10carbon atoms, R and R are selected from the group consisting of hydrogenand alkyl groups containing about 1 to about 3 carbon atoms and x is aninteger from 1 to 2.

11. A gasoline benefiting concentrate consisting essentially of about 23to about 60 percent by weight of tetraethyl lead, about 13 to about 36percent by Weight of a mixture of ethylene halides and about 3 to about63 percent by weight of a tri(butoxyethyl) phosphate, thetri(butoxyethyl) phosphate being present in at least 0.1

times the theoretical amount required to convert the lead in saidtetraethyl lead to lead phosphate.

References Cited in the tile of this patent UNITED STATES PATENTS2,372,244 Adams et a1 Mar. 27, 1945 2,405,560 Campbell Aug. 13, 19462,427,173 Withrow Sept. 9, 1947 2,477,220 V011 et a1. July 26, 19492,667,234 Hasche Jan. 26, 1954 2,723,237 Ferrin Nov. 8, 1955 2,794,719Bartleson June 4, 1957 2,797,153 Bereslavsky June 25, 1957 2,820,766Elliott et al. Jan. 21, 1958 2,851,343 Cantrell et a1 Sept. 9, 1958FOREIGN PATENTS 600,191 Great Britain Apr. 2, 1948 683,405 Great BritainNov. 26, 1952 733,820 Great Britain July 20, 1955 1,100,185 France Sept.16, 1955 UNITED STATES PATENT'OFFICE CERTIFICATE OF CORRECTION PatentNo. 3 009 790 I 7 November .21 1961 John Pv Pellegrini Jr at al,

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 7,, line 29 for "in" read me is g column 14 line 19 for"cumbustion" read combustion 3 column 16 line YO for "0.004"- read0.0004

Signed and sealed this 10th day of April 1962..

(SEAL) Attest:

ERNEST in SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

6. A GASLINE MOTOR FUEL COMPRISING A MAJOR AMOUNT OF GASOLINE CONTAININGABOUT 1 TO ABOUT 3 CUBIC CENTIMETERS OF TETRAETHYL LEAD PER GALLON OFGASOLINE TO PRODUCE A GASOLINE FUEL COMPOSITION HAVING A MOTOR OCTANENUMBER OF AT LEAST ABOUT 85 AND A RESEARCH OCTANE NUMBER OF AT LEAST 95,BETWEEN ABOUT 0.0047 AND ABOUT 0.14 PERCENT BY WEIGHT OFTRI(BUTOXYETHYL) PHOSPHATE, THE TRI(BUTOXYETHYL) PHOSPHATE COMPRISING ATLEAST ABOUT 0.1 TIMES THE THEORETICAL REQUIRED TO COVERED TO CONVERT THELEAD IN SAID TETRAETHYL LEAD TO LEAD PHOSPHATE AND ABOUT 0.25 TO ABOUT0.75 PERCENT BY VOLUME OF LIGHT LUBRICATING DISTILLATE OIL HAVING AVISCOSITY AT 100*F. OF FROM ABOUT 50 TO ABOUT 500 SAYBOLT UNIVERSALSECONDS.